#正则
import re
rs = re.match('.','abcd')
print(rs.group())
rs = re.match('...','abcd')
print(rs.group())
rs = re.match('\s','\t')
print(rs.group())
rs = re.match('[ab]','abcd')
print(rs)
rs = re.match('[0-9]*','45555')
print(rs)

